Telescoping rotor



1957 J. B. ALEXANDER 2,776,017

TELESCOPING ROTOR Filed April 1 53 5 Sheets-Shem 1 V (5.95 B. ALEXANDEE,

H IN V EN TOR. 9%

ATTORNE').

1957 J. B. ALEXANDER TELESCOPING ROTOR 3 Sheets-Sheet 2 Filed April 20,1953 44 WA ///V/V/ Q Rm w m .E w Mm m A B My W 5 7 m m autm m H 1957 J.B. ALEXANDER 2,776,017

TELESCOPING ROTOR Filed April 20, 1953 3 Sheets-Shem 3' a J J4 2? Q 4447 a 7 1 34 49, -.uas g5 1:. a? 7% Hr? 40 7- 11- 50 7% a T- I:

17 6? 51 7 J9 I I I, 5/

J z 5? if .9. 7 54 E 65 g 66 F 68 67 rI-sss B AL EXANDEE,

INVENTOR.

United States Patent '0 TELESCOPING ROTOR Jesse B. Alexauder,-Anaheim,Califi, assignor to Gifford H. Teeple, Los Angeles, Calili, as trusteeApplication April 20, 1953, Serial'No: 349,651 3 Claims. (Cl. 170-16011)The present invention relates .to a telescoping rotor .of a type whichis useful as an aerial deliverydevicqin that .itis capable of carryingheavy loads-at a high rate of descent, and which. high rate of descentmay be abruptly checked to the end that cargo to be delivered may helanded at a reduced rate, so that the rotating blades .will

as a retractable braking surface for jet aircraft may be utilized bothin the air and on the ground. By extending the rotor in the same manneras airplane landinggears are extended, and while the rotor is retractedto its smallest diameter, the rotor will serve as suflicientdrag toincrease the angle of approach before landing. After landing, the rotormay be allowed to extend to its diameter to brake the airplane on thelanding roll. 1 While not shown here, the application of power to theblade tips of the rotor provides a means of increasingjthe effectivedrag of the rotor several timesthat of autorot'ation, all of which iswithin the scope of the invention.

1 A further object of the invention is the provision in a rotor havingtelescoping blades of a construction wherein the blade sectionsprogressively and equally moveloutwardly as the rotor spins.

A further object of the invention is to provide positive means forretracting the sections of a telescoping blade rotor at a given speedand simultaneous to. landingthe said rotor.

A further object is the provision of a rotor which may be directionallycontrolled during descent thereof.

A further object is the provision of a rotor which may be launched fromaircraft moving at high velocities.

A further object is the provision of a rotor which may be controlled asto its rate of descent.

In the drawings:

Figure 1 is an elevation of the rotor shown carrying a load,

Figure 2 is a fragmentary view looking in the direction of the arrows 22of Figure 1,

Figure 3 is a fragmentary elevation of oneof'the blades shown extendedand at a changed angle of incidence from that of Figures 1 and 2,

Figure 4 is a view looking in the direction of the arrow 44 of Figure 3,

Figure 5 is a fragmentary sectional view on the line 5-5 of Figure l,and on an enlargedscale,

Figure 6 is a fragmentary sectional view on the line 6-6 of Figure 5,

Figure 7 is a fragmentary sectional view on the line 7-7 of Figure 6,

Figure-8 is a view similar to Figure 6, certain' parts being in movedrelationship,

pair of .diametric telescoping blades 1 and 2, each made up of sections3, 4, 5 and 6. The sections 3 are fixed to a hub 7 while sections 4,5and 6 are telescopically related. The sections-3 are provided withinwardly directed flanges .at the ends thereof, as shown in Figure 11,at '3, while the section 4 has an external end flange 9. When thesections have been extended from "their nested ortelescopedrelationship, the flanges 8 and 9 are in contact to limitfurther outwardmovement of the section 4. This flange construction iscontinued for the remaining sections, which is to say that the oppositeend of section '4. is provided with an inwardly directed flange, whilethe section 5 has an external flange for cooperation with the inwardlydirected flange of section 4, the opposite end of section 5 havinganinwardly directed flange end section 6 having an external flange forcooperation therewith. The

outermost end of section 6 is provided with a plate or flange 10' havingthesame profile as the outermost end of section" 3. Thus,iwhen the.sections 4,5 and 6 are nested "within'the section'3, the plate 10,closes the end of section3.

The innermost end of each section 3 is provided with an attaching angleplate 11. Secured to the plate 11 is an outwardly extending stud 12. InFigure 5, this stud is shown as headed, at 13, and secured to said plate11 by brazing, welding, or other means, so that the stud rotateswhen theangle of incidence of the blade is changed.

The studs for each of the blades is passed through the endwalls 14 andl5 of the hub casing or housing, and said hub housing has'twosubstantially parallel side walls at 16 and 17, enclosing the end walls,and a top wall or cover 18' which overlies the side and end walls. Noparticular-means is shown for securing the walls inworking-relationship. The endwalls 14 and 15,are integral The said studseach carry a boss 24 provided with diametrically extending arms 25andl26. Each stud 12 is screw-threaded at 27. to receive a nut 28 forsecuring a boss 24 in position of service, andin such manner that anychange in the angle of incidence of the blades 1 or 2 Will producerotation of the stud and of the arms 25 and 26.

Substantially intermediately positioned between the walls 14 and. 15 andextending between the sides 16 and 17 is a shaft 29. This shaft isprovided with a disc type head 30, which head overlies a washer 31 whichabuts the external surface of the side 16. The opposite end of the shaftis reduced in diameter, at 32, and passed through an opening in the side17, the reduced diameter portion being externally screw threaded at 33.Carried on the reduced diameter portion 32 are a pair of washers 34 and35, the assembly being secured by a nut 36 received onthe screw-threads33. The construction just described, to wit, the head 30, washer 31, andthe two washers 34 and 35, function as brakes to regulate rotation ofthe shaft and 31, 34 and 35 into compressive engagement.

Carried on the shaft 29 is a boss 37 provided with a pair of diametricarms 38 and 39, the arms being of a length sufiicient to cross the arms25 and 26. The said boss is provided with a catch 40. Mounted on theside wall 16 by means of a pin 41 is a lever 42 provided with a detent43 adapted to cooperate with the catch 40. In the construction shown, Ihave provided a spring 44 having a portion coiled about the pin 41 andsecured to the wall 16 at one end thereof, while the opposite endportion of the spring underlies the lever 42 to normally swing the leverin a counter-clockwise direction, viewing Figure 6. The lever 39 isnormally urged to rotate in a clockwise direction, as indicated by thearrow 45, by a coil spring 46 interposed between the base 19 and saidlever. Thus, in the construction shown, if the detent 43 is lifted fromthe catch 40, the arms 38 and 39 will rotate in the direction of thearrow 45, and in so doing, arm 26 will be moved upwardly, thus turningthe blade 1, while the arm 25 for blade 2 will be depressed, each blade,therefore, being given the same turning angle of incidence. However,movement of the arm 42 is under control, and said arm is not allowed torelease the detent from the catch until the rotor has reached a selectedelevation above a landing surface.

Mounted upon the shaft 29 is a spool or pulley 47. Secured to saidpulley are tapes or cables 48 and 49. Each tape is fastened to a bladetip, that is, the outermost end of each tape is fastened to the section6 adjacent the plate 10. Assuming the blades in the extended positionshown in Figure 1, upon revolving the pulley, the respective tapes willwind upon the pulley and progressively retract the sections within thefixed sections 3.

Fixedly secured to the shaft 29, and adjacent one end of the pulley is abevel gear 50. Bevel gear 50 is in mesh with the teeth of a furtherbevel gear 51 which directly controls the rotation of the pulley 47,under certain conditions of operation of the rotor. The annulardepending portion 20 of the hub housing confines upper and lower bearingmembers 52 and 53 comprising pairs of races, with interposed ballstherebetween. Specifically, the annular housing portion 20 is internallyshouldered at 54 and 55 so as to accommodate the upper and loweroutermost races. The innermost races surround a tube 56, this tube beingof extended length and made up of sections as shown in Figure l, at 57and 58, the sections being held together in the same manner as the bladesections, which is to say, flanged internally and externally so thatsaid sections are held in telescopic working relationship. The tube 56,together with its sections 57 and 58, carry the load shown at 59. Tube56 is internally threaded at 60 for connection with a fitting 61, whichfitting is flanged so as to overlie one of the uppermost races. Fitting61 is externally screw-threaded at 62, and passed through said fittingis a tubular shaft 63, the bevel gear 51 being locked to the upper endof said tubular shaft. The lowermost end of said tubular shaft carriesan annular disk 64 positioned within the tube 56.

A collar 65 is carried upon the tubular member 56, and supports theinner race of bearing member 53. Immediately below said collar 65 is anannular disc type race member 66 and a second annular disc type racemember 67, between which race members are balls 68. The tubular member56 is slotted at 69 to permit passage of an arm 70 therethrough, one endof said arm being pinned to a lug 71 carried by an annular disc 72 whichsurrounds the tubular shaft 63. The disc 72 is adapted to bear against adisc 74 which surrounds the tubular shaft 63 and is positioned betweenthe discs 72 and 64. The disc 74 is formed of fibrous material, such asused for brakes. A bracket 75 depends from an annular portion 20 and alever 76 is pinned thereto. One end of said lever is pinned to a lug 77carried by the race member 66. The outermost end of said lever '76 hassecured thereto a link 78, which link is passed through an opening 79 inthe base 19, and then is secured to the arm 26.

What is termed a safety catch includes a nut 80 adapted to bescrew-threaded to the threads 62 of the fitting 61, there being an arm81 extending radially from said nut, and a pin 82, secured to one end ofsaid arm 81, is passed through a guide bracket 83, the bracket beingsecured to the base 19. A cable 84 is secured between pin 82 and the arm42, at 85. Thus, in the position of the parts, as viewed in Figure 6,the cable 84 is taut and the arm 42 is so held that the detent portion43 cannot escape from the catch 40. Also secured to the arm 42 is oneend of a cable 86. Cable 86 is housed in a sheathing 87, the saidsheathing being centered within the tubular shaft 63 at spaced points.The centering of the sheathing may be accomplished by providing one ormore roller type bearings housed in suitable race members, as shown. Thecable and a part of its sheathing extends through a slot in the tubularmember 56, the said cable 86 being of extended length, as shown inFigure 1, with the lowermost end thereof carrying a weight, such as aplumb bob 88.

In Figure 10, 1 have shown a modification of the means for brakingrotation of gear 51, and wherein a bracket 89 carries a lever 90, theoutermost end of the lever being linked, by means 91, to one of the arms25 or 26, in this instance, the arm 25, while the opposite end of saidlever is secured to a brake means 92, in part surrounding the hub ofgear 51.

The operation, uses and advantages of the invention just described, areas follows:

Assuming that the rotor is to be used for delivering a load 59, therotor is carried in the fuselage of the aeroplane, with the sections ofthe blades 1 and 2 telescoped, that is, nested together in the interestof saving space. Also, the sections 57 and 58, and a portion of the tube56, are nested. If, at a predetermined height, the rotor with its loadis released from the aeroplane, the load carrying tubes 56, 57 and 58,will move to the extended position shown in Figure 1, and the rotor willcommence rotation, the blade sections being nested, as shown in Fig. 12,and at a zero angle of incidence (see Figure 2). At zero angle ofincidence, the parts within the hub are in the positions shown inFigures 5, 6 and 7. The nut 80 of the safety catch is fully screwed uponthe threads 62 so that the lever 42 has its detent engaging the catch 40and the arms 38 and 39 are in a canted position, as shown in Figure 6,with the spring 46 compressed. Furthermore, the tapes or cables 48 and49 are wound upon the pulley. The rotor will auto-rotate and the loadwill fall very rapidly. Previous determination has indicated the speedof rotation of the blades required to move the sections (undercentrifugal force) outwardly from their nested telescoped position, andthis is regulated by adjusting the nut 36, which effects frictionalengagement between the parts 30, 31, and 34 and 35.

Assuming that auto-rotation has increased to revolutions per minute, thesections 4 commence moving from the fixed sections 3, followed bymovement of sections 5 outwardly from sections 4, and then the outermostsections 6 move from sections 5. All of the sections move at a definiterate, progressively, and at equal distances for each blade, this beingcontrolled in that the outermost sections 6 are provided with plates 10,and sections 6 cannot move except as the pulley 47 rotates and allowsthe tapes or cables 48 and'49 to move. The end plates 10 prevent othersections from moving unevenly, the control being entirely through thesections 6 and the end plates 10, it being remembered that the endplates 10 have the same profile as the ends of the fixed sections 3.When the blades are extended with the plumb bob 88 hanging downwardly,the blades and the hub 7 are rotating, and there is no relative rotationbetween the gears 50 and 51. The gear 51 is mounted upon the tubularshaft 63, which is free to rotate within the tube 56; the bearings at 52and 53, however, allow the hub housing to rotate without communicatingsuch rotation to the tube 56. In other words, the load, 59, the tube 56and its sections 57 and 58, are non-rotating. As the hub rotates throughthe air, the safety catch will unscrew from the threads 62 and move tothe position shown in Figure 8, which releases the cord or or cable 84.The cord or cable 86, however, remains substantially taut, as it dependsbelow the load 59 a certain distance and is held by the plumb bob 88, asin Figure 1. The safety catch assures that until the rotor is in the airand actually rotating, the detent 43 will not escape from the catch 40to release the arm 42. As the rotor descends, a point above the groundwill be reached at which the plumb bob 88 will contact the earth, asshown in Figure 1, which will immediately release tension in the cable86 and permit the arm 42 to move from the position of Figure 6 underaction of the spring 44 to the position shown in Figure 8. When thisoccurs, the spring 46 immediately expands to rotate the arms 38 and 39,and such rotation produces movement of the arms 25 and 26 to change theangle of incidence of the blades 1 and 2, and move the said blades froma zero angle of incidence to the angle 'of maximum lift, shown inFigures 3 and 4. This immediately slows the descent of both the rotorand its load. At the same time that the angle of incidence of the bladesis changed, braking action occurs through the medium of the link 78 tomove the plate 72 and braking disc 74 into engagement with the disc 64carried on the end of the tubular shaft 63. This braking tends to stoprotation of the tubular shaft 63, and hence stops rotation of the gear51. If rotation of the gear 51 is stopped, then gear 50 starts rotationby traveling around the teeth of the stationary gear 51, and in sodoing, the pulley 47 is rotated, and the tapes or cables are rovethereabout to retract the sections 4, 5 and 6 of the blades within thefixed sections 3. The load is then landed and the danger of anycart-wheeling of the blades along the ground is effectively overcome.

I have thus provided a rotor which is useful for many purposes, andwhich assures a rapid descent for a given fall of the rotor and itsload, followed by a sudden checking of the descent and a nesting of thetelescoping blade sections.

It is evident from the foregoing statement that a certain sequence inoperation of the rotor occurs, to wit: the rotor falls with its load ata given rate of speed, the blades being at zero angle of incidence;secondly, that when the plumb bob strikes a surface, tension on the cord86 is released to permit mechanism within the hub to change the angle ofincidence of the blades from Zero to maximum lift. This change in angleof incidence increases the lift, and slows rotation of the rotor; andthirdly, the brake comes into operation and progressively functionsthrough the bevel gears to retract the movable sections of each blade.However, this retraction is slow as the braking action has a certainamount of slippage and the blades are under load. The length of thecable or cord 86 may be determined either by calculation or byexperiment and so that the free falling of the rotor may be at 100 feetper second and gradually reduced upon the plumb bob striking the earthto a fall of 25 feet per second, as a landing speed.

After the load is landed, the rotor may be made ready for re-use bymaintaining a tension upon the cord or cable 86 and revolving the bladesto zero angle of incidence, which will cause the detent 40 to engage the6 catch 43. The operator turns the tube 56, which will cause the nut tore-engage the threads 62, whereupon cord 86 may be released and therotor is again ready for use.

I claim:

1. In rotor construction, a hub, blades extending from said hub, eachblade including a fixed section and movable sections for telescopicreception within the fixed sections, means rockably mounting the fixedsections of each blade to the hub, a shaft within the hub, diametricarms rockably mounted on said shaft, means extending from each fixedsection of the blades for engagement with said arms to be moved by saidarms to vary the angle of incidence of said blades; releasable means forsaid arms for holding the arms in a defined position which, whenreleased, permits the said arms to rock and engage the second namedmeans, and means for moving said arms when said releasable means isreleased.

2. In rotor construction, a hub, blades extending from said hub, eachblade having movable sections in telescopic engagement, a stud shaftfixed to each blade for mounting each blade to the hub, a shaft withinthe hub, arms carried on said second named shaft, means fixedly securedto said blades adapted to be engaged by said arms to turn the studshafts to vary the angle of incidence of said blades from an initialzero lift position to maximum lift position, a spool carried on saidsecond named shaft, cables on said spool and connected to the outermostsections of each blade, a bevel gear on said second named shaft, asecond bevel gear rotatively mounted in the hub and in mesh with thefirst bevel gear, releasable means for holding the arms in one position,a brake operable to prevent rotation of the second bevel gear, meansmoving said arms when released by said releasable means to cause saidarms to engage the first means to change the angle of incidence of theblades from zero lift to maximum lift, and a link between the brake andone of said arms to actuate said brake when the arms are moved to retardrotation of the second bevel gear, the first bevel gear having planetarymotion therearound to rotate the spool and cause the cables to retractthe movable sections of each blade.

3. In rotor construction, a hub, blades extending from said hub, studshafts fixedly mounted to said blades and rotatably mounted to the hub,each stud shaft provided with a pin, a shaft within said hub, a pair ofarms rockably mounted on said second named shaft, the said arms adaptedto engage the said pins on the stud shafts, means for urging said armsto move against said pins and vary the angle of incidence of said bladesfrom zero lift to maximum lift, releasable means normally preventingmovement of said arms to engage the said pins, said releasable meanswhen actuated releasing the arms for movement by said first named meansto cause the said arms to engage the said pins to vary the angle ofincidence of said blades.

References Cited in the file of this patent UNITED STATES PATENTS1,919,089 Breguet et al. July 18, 1933 1,922,866 Rosenberg et al. Aug.15, 1933 2,108,245 Ash Feb. 15, 1938 2,509,481 Crise May 30, 19502,637,406 Isacco May 5, 1953

